1. Field of the Invention
The inventions disclosed and taught herein relate generally to monitoring a load in a power distribution system; and, more specifically, relate to a method and apparatus for remotely monitoring a load in a power distribution system adapted to validate the performance of a load sensing in an apparatus.
2. Description of the Related Art
In order to provide background information so that the invention may be completely understood and appreciated in its proper context, reference may be made to a number of prior U.S. patents as follows:
U.S. Pat. No. 5,281,859 to Crane, issued Jan. 25, 1994, discloses an “automatically switched power receptacle,” in which a switched power circuit selectively connects an electrical load to any one of a plurality of branch power circuits. The switched power circuit includes a sensing circuit for sensing electrical loading on each of the branch circuits. A logic circuit is coupled to the sensing circuit for selecting one of the branch circuits to be connected to the load according to the sensed loading to provide balanced loading on each branch circuit.
U.S. Pat. No. 5,424,903 to Schreiber, issued Jun. 13, 1995, discloses an “intelligent power switcher,” in which an intelligent power switching system is disclosed for controlling the electrical connection of a power source to each of a plurality of outputs, such as personal computers components or electronic entertainment equipment. Switch circuitry is coupled to relay circuitry for generating signals responsive to user commands to select an “on” or “off” state with respect to each output.
U.S. Pat. No. 5,862,393 to Davis, issued Jan. 19, 1999, discloses a “system for managing power of a computer with removable devices.” The patent discloses a system for managing power consumption by communicating power management events to a removable device of the computer. In response to a power management event, a device removal signal is transmitted to a device controller for the removable device while the device is installed within a socket of a computer. This device removal signal can provide notice of a power state change for the device, such as the interruption of electrical power to that device. The power state change is communicated by the device controller to a device driver in response to the device removal signal. Electrical power to the device is terminated in response to the power management event. Additionally, a device insertion signal is transmitted to the device controller in response to another power management event and while the device remains installed within the socket. This device insertion signal provides notice of another state change for the device. Electrical power is reapplied to the device in response to this power management event.
U.S. Pat. No. 6,618,772 to Kao et al., issued Sep. 9, 2003, discloses a “method and apparatus for selecting, monitoring, and controlling electrically powered devices.” In one embodiment, the apparatus includes an electrically powered device having a key operating line and switching control circuitry to control usage of the electrically powered device by interrupting continuity of the key operating line.
U.S. Pat. No. 6,741,442 to McNally, issued May 25, 2004, discloses an “intelligent power distribution system,” which discloses one or more intelligent power strips. The power strips can each include an elongated housing that may be adapted for mounting in an equipment rack. The power strips further include power management circuitry that can power-on and power-off the power outlets in accordance with an operator defined sequence and delays. The power management circuitry can further sense electrical current drawn by the power strip and control operation of the power strip based on the sensed electrical current to minimize branch circuit breaker tripping.
U.S. Pat. No. 6,744,150 to Rendic, issued Jun. 1, 2004, discloses an “outlet strip controlled by PC using low voltage powertap.” The patent discloses an improved electrical power strip which will automatically energize or de-energize one or more devices which are plugged into the strip, upon receiving an electrical signal from the primary device, without need for manual actuation of a switch on the electrical strip or an under monitor system by the user. The system uses a low voltage power tap connector which is plugged in any appropriate socket of the primary device (which may be a personal computer) to sense the primary status of the power supply. The output signal triggers a synchronous transfer switch or relay which enables power to secondary devices, permitting them to be synchronously turned on or off depending on the computer status.
U.S. Pat. No. 6,937,461 to Donahue, IV, issued Aug. 30, 2005 discloses a “modular power distribution unit, module for the power distribution unit, and method of using the same.” The patent discloses a modular power distribution unit for supplying electric power to attached equipment in environments such as data centers, computer rooms, and communication centers, where power requirement for attached equipment may vary. The power distribution unit includes a frame and one or more user-replaceable power modules, which fit into slots in the frame. Each power module provides one or more plug receptacle types, receptacle numbers, and power rating configuration to accommodate various equipment in a particular environment, as needed. The power modules may be removed, installed and interchanged in the frame without interrupting power to other modules or to the power distribution unit.
None of the references teaches solving the above patent problem, that is remotely measuring and detecting and qualifying certain power-related anomalies or line disturbances caused or created by the electrical loads and validating the performance of the electrical load sensing in the apparatus. There remains then a need for proper and accurate measuring of the power-related signals of the electrical loads, current levels and/or voltage levels and calibration of the same in a remote fashion and while the loads are still operative.
The inventions disclosed and taught herein are directed to a method and apparatus for monitoring a load.